impulse
by Miah-Chan
Summary: Keith knows he's impulsive. It's not a secret, least of all to himself, and he's never been especially interested in curbing this particular trait of his. Being quick to respond, letting his body act before his brain can catch up, has saved his ass more often than burned it... Until it nearly has him kissing his superior officer in the middle of a grappling match.


a /super late asldkjf/ birthday fic for my sweet kitten Darcy 3 find her (& her awesome MakoHaru fics!) on Tumblr l1nkp1t

 **Some Notes:**  
 ***** This was written _prior_ to seasons 6 & 7, so please consider this more or less an AU. I imagined Shiro to be only a year or two older than Keith, who is around 17 here. I do not personally ship Sheith, but I love to make my friends happy, and I could understand the appeal of this ship before certain scenes were revealed in canon.

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Keith knows he's impulsive. It's not a secret, least of all to himself, and he's never been especially interested in curbing this particular trait of his. Being quick to respond, letting his body act before his brain can catch up, has saved his ass more often than burned it, so he's content to think of it as an occasional double-edged sword.

Until it nearly has him kissing his superior officer in the middle of a grappling match.

They're alone, thankfully; it's one of their late night training sessions because Keith's too wired to sleep and Shiro is a saint who'll suffer sleep deprivation for him (though Keith can't fathom _why_ ). Plus, he's the only one with the authority—and willingness—to unlock the gym at ass'o'clock in the morning. He knows Keith struggles with insomnia—he knows more about Keith than anyone, really, and sometimes he still wonders how Shiro managed it when Keith _knows_ he's as easy to befriend as a defensive porcupine—so he doesn't feel the need to ask questions or pry. He just flips on the lights, drags out the mats, and waits with an easy smile on his handsome face.

Keith will never tell him, but many nights he can attribute his insomnia to thoughts of the man himself. And after tonight, he's pretty sure he's going to have to find some other activity to wear himself out because he's not sure he'll ever be able to look Shiro in the face again.

Keith isn't great at subtlety; it kind of goes hand-in-hand with his impulsiveness. So he knows it's painfully obvious _exactly_ what's on his mind when he freezes in the middle of a move. He's got Shiro pinned to the floor, trapping him in a push choke with one hand and holding one of Shiro's securely above his head, and he's hyper-aware of how it feels to have Takashi Shirogane trapped between his thighs. Their chests brush with every harsh panting breath and Keith finds it impossible to look away from those dark eyes—until Shiro licks his lips. They're perfect, Keith thinks dazedly, a cupid's bow over a full lower lip just _made_ for biting. And Keith very much wants to have a taste, to nibble his way from that flawless mouth to that square jaw until he's trailing down Shiro's neck, until—

Heart hammering in his throat, Keith realizes he's only centimeters away from acting on those thoughts, and he flings himself none too gracefully away. His face burns with embarrassment and shame; Shiro's friendship is the best thing that's happened to him in a long time and he almost ruined it—may still have ruined it—over stupid teenage _hormones_. He groans, hiding his face in his palms.

"Shit," he mutters, the only sound in the vast gym aside from the shuffling from Shiro's direction as he presumably sits up.

"Keith?" Shiro calls softly, and oh, wow, his voice is way closer than Keith expected. He peeks cautiously between his fingers, just enough to see that Shiro has crawled over so that he's kneeling right in front of Keith, before drawing his knees up to further shield himself.

"Sorry, it's nothing," he rushes to assure, knowing everything about his posture is screaming in opposition to his words. "Just give me a minute."

"Keith, it's fine," Shiro says gently, which only makes him squeeze his eyes shut. Of course Shiro would say that; it's not in his nature to be cruel. His quiet understanding only serves to make Keith feel worse.

There's a moment of silence between them as Keith tries to collect himself before Shiro sighs. There's more shuffling and then Shiro's hands are encircling Keith's wrists lightly; not pulling, just resting as he softly requests, "Hey, will you look at me, please?"

Keith wants to shake his head, to refuse until Shiro drops the subject and pretends it never happened, but he can't. He knows he can't run away from this, and truthfully he doesn't want to run away from his feelings for Shiro—he just doesn't want to drive Shiro away from _him_. He takes a few deep breaths to steel himself, then slowly lifts his head from his hands, but avoids meeting Shiro's eyes directly.

It makes Shiro chuckle, releasing one of Keith's wrists to poke his cheek playfully as he teases, "That's not exactly what I meant, you know." Keith huffs, sliding his gaze to Shiro with intent for it to be quick, but he finds himself staring again at the fond expression he's wearing. Shiro smiles warmly at him, eyes soft with understanding, and Keith jolts when he feels a hand cupping his cheek.

"There, that's better," he murmurs, voice low as if he's afraid he'll spook Keith. He rubs his thumb over the curve of Keith's cheek, throwing his heart into overdrive.

"Shiro, I'm sorry," he manages to grit out between his clenched teeth, twisting his fingers anxiously. "Just forg—"

"Don't apologize, or I'll think you didn't mean it." Shiro interrupts, grinning cheekily. Keith stares at him for a moment, trying to process what he means versus what Keith _wants_ him to mean, trying to decide if it's possible they're the same thing. He's pretty sure Shiro can see the way his brain is short-circuiting right now, if the amused snicker is anything to go by.

"I—but you—we can't," Keith stammers weakly, feeling dizzy. Shiro is his _superior officer_ , he's supposed to be the one enforcing rules and keeping unruly, hormonal cadets in their place, not _encouraging fraternization_.

Shiro breaks through his spiraling thoughts with a hum, tucking loose strands of hair behind Keith's ear as he says nonchalantly, "I mean, I understand if you don't want to…"

"Oh come on," Keith snaps irritably, because really? He's going to try to play dumb _now_? " _Clearly_ I want to, I think that much is obvious. I just…I mean…" The sudden bravado drains out of him, replaced with what feels like shyness. He glances away only to look back again from beneath his lashes as he continues quietly, "You don't have to."

Shiro's eyebrows raise almost comically high as he replies incredulously, "Are you kidding? What part of tonight has made you think I don't want to?"

"I don't know," Keith huffs, dropping his knees so he's sitting cross-legged instead. Shiro drops his hand from where he's been cradling his cheek, but slides his other from where he's been holding his wrist until they're touching palms. He interweaves their fingers painstakingly slowly, giving Keith plenty of time to pull away should he want to.

Keith really, really doesn't want to.

"Keith," calls Shiro, voice low and husky around the edges; it has Keith meeting his eyes effortlessly, drawn in like a siren song, and he vaguely notices that they're leaning into one another's space. He sees the exact moment Shiro decides to challenge him, the way he quirks a brow expectantly before saying in a faux-instructor tone, "It's important to finish the things you start."

And nothing, not alien abduction or Commander Iverson's wrath, could have stopped Keith from taking the bait.

All doubt erased, he surges forward the few remaining centimeters to press his mouth to Shiro's with an urgency and hunger even he hadn't completely understood until now. Kissing Shiro is everything he's imagined it might be, and more; now that he's had a taste he doesn't know if he'll ever be satisfied again.

Despite his teasing, Shiro meets him halfway, the slide of his lips slightly crooked with the smile he can't quite hold back. He sighs through his nose happily, releasing Keith's hand to trail warm fingers up his neck until he's cradling Keith's jaw in his hands, angling him just so. He pulls away only to dive in again, and again, a similar need evident in the grip of his fingers against Keith's cheeks, in the desperate press of his mouth.

Keith hums, parting his lips in invitation that Shiro is eager to accept. They explore one another languidly, the urgency melting away into a need to savor, until Keith gives in to earlier temptation, tugging Shiro's bottom lip between his teeth experimentally. The sound it pulls out of Shiro has him grinning but, before he can go any further, Shiro pulls away.

The noise of protest Keith makes sounds suspiciously like a whine; he opens his eyes to frown bewilderedly at Shiro who gives him a sheepish smile.

"You really do go all-out in everything, don't you?" he laughs breathlessly, pulling Keith in for a more chaste peck before retreating again. Keith isn't even ashamed at the way he tries to chase after, just miffed that it's all ending so soon which Shiro seems to sense given the smirk on his significantly redder lips. Satisfaction and pride bloom in Keith's chest; _he_ did that, made Shiro look mussed and pink-cheeked, breath coming just a bit too quickly.

He hopes he'll get to do it again, preferably repeatedly and often. Which, judging by the way Shiro is beaming, he thinks is highly probable.

"Well, can't just half-ass it, right?" Keith finally replies, quirking a brow cheekily. Shiro's answering laughter echoes through the gym, deep and full of affection; it soothes the fire burning in Keith's chest into a homely warmth, makes him feel sappy and gooey inside and all manner of hopelessly moonstruck. He knows the look on his face is probably dopey, revealing entirely too much, but he can't find it in himself to mind. Not if it's Shiro who sees.

And he does see, sees Keith for everything he is and everything he's not and everything he hopes to be—he's seen it all and still chose to stay by Keith.

So maybe Keith is being selfish for wanting Shiro in this way too, maybe he's being impulsive and reckless like everyone has always chastised him for, but he can't find it in himself to care.

"C'mon," Shiro swoops in, dropping another quick kiss on Keith's lips, before pulling back to stand. He holds out a hand to help him up, continuing, "We should head back. Next patrol is due soon and we wouldn't want our secret lovers' den discovered."

"Oh my god," Keith groans, slapping a hand over his rapidly heating face, "Please shut up." He takes Shiro's hand anyway, choosing to ignore the way Shiro does nothing to muffle his laughter.

"What? It's true, isn't it?" he asks, tone too amused to pass as innocent, though he tries. His smug grin doesn't help. "We meet under the cover of darkness, in a forgotten gym with shitty security cameras, and—" Keith shoves his shoulder as he passes, trotting across the mats to gather his water bottle and towel as he urges the blush in his cheeks to fade. Shiro snickers behind him, but takes the hint, and begins gathering the mats to return them to their storage closet. It's not long before they've properly cleared the gym and are locking the doors behind them.

There's an easy quiet between them as they walk back to the dorms, slower than usual though neither remarks on it. Their hands brush a number of times until Shiro reaches out and links their pinkies, face turned away in a surprisingly shy gesture that makes Keith's heart pound. He tightens his grip with a soft smile, looking up at the stars.

And if he chooses to rely on impulse again, pulling Shiro off the path just before reaching his dorm and into the shadows for another (entirely less chaste) kiss, well, he's never been especially interested in curbing that particular trait of his.

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Thanks for reading! As always, I'd love to hear your thoughts!

I update most regularly on AO3 Miah_Kat, if you're interested! ^^


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